1. Field
Methods and apparatuses consistent with the exemplary embodiments relate to measuring an otoacoustic emission (OAE), and more particularly, to a method and apparatus for measuring an OAE, which have a short OAE measuring time and are reliable by minutely measuring only signals in a required section while measuring the OAE.
2. Description of the Related Art
An example of a method of measuring an auditory characteristic includes a pure tone audiometry (PTA) method of measuring a value of the threshold of audibility as a subject responds when a constant reference sound is heard. The PTA method is not convenient for measuring an auditory characteristic in a middle band, and the concentration and selection of the subject affects a result of the PTA method.
On the other hand, a method of measuring an otoacoustic emission (OAE) measures an auditory characteristic without a reaction of a subject. The OAE is sound generated in the ear, i.e., sound energy generated according to an active amplification action of an outer hair cell (OHC) inside a cochlea. Since damage of the OHC largely causes hearing loss, the auditory characteristic of the subject may be measured by measuring a reaction of the OHC according to frequencies and input levels.
Generally, in order to measure the OAE, a signal corresponding to a predetermined frequency and a predetermined input level is transmitted to the subject and the signal received by the ear of the subject is measured. This process is repeated after changing the frequency and the input level of the signal.
When the OAE is measured according to signals having different frequencies but the same input levels, a section in which values of the OAE change remarkably may be generated due to the intrinsic characteristics of the OAE. Alternatively, when the OAE is measured according to signals having the same frequencies but different input levels, a section in which values of the OAE are different from auditory characteristic of the subject may be generated. Accordingly, a reliable method of measuring OAE is required.
Also, unnecessary information is generated when the OAE is measured for all possible combinations of frequencies and input levels so as to measure the OAE in frequencies and input levels in wide ranges.